30 BOTANICAL GAZETTE [ory 
previous fusion of the two polar nuclei. At the base of the 4 
embryo-sac are the distorted remains of three antipodal nuclei 4 
still separated from the main cavity by a distinct cell-wall. It 
was impossible to determine whether this had been formed — 
anew, or whether the old perforated wall had simply been g 
repaired. - 
At the time when the main features of this study of Conval- j 
laria were read at the Boston meeting of the American Associa- 
tion for the Advancement of Science, so far as the writer was 
aware no exactly similar case had been observed. Mann? had 
discovered a cross wall in the embryo-sac of Myosurus, but here 
the development seems to have been somewhat different ; and 
Strasburger3 had figured a structure somewhat resembling 4 
cross-wall in the embryo-sac of Allium, although it was men- 
tioned in the text as a plasma-plate. Since that time, however, 
McKenney* in making a careful study of the embryo-sac of 
Scilla has described a process very similar to that in Convallaria. 
The archesporial nucleus underwent a period of growth before 
dividing. The first division showed the reduced number of 
chromosomes and was followed by a cell-wall. The two suc- 
ceeding divisions in each daughter cell were not followed by @ 
cell-wall, so that as a result two cells were present, each con- 
taining four nuclei. Up to this point the process was similar to 
Convallaria, but it was further found that only the upper cell 
took part in the formation of the embryo-sac, and not both 
in Convallaria, while the lower cell disintegrated. 
The process in Convallaria is strikingly similar to that im 
Lilium, and is probably to be considered as simply a modifi-. 
cation of that method or a transition to it from the ordinary 
type with two or four cells in the axial row. It differs merely 
in the possession of a cross-wall, which however partially or 
*MANN: The embryo-sac of Myosurus minimus L. Trans. and Proc. Bot. Soe 
Edinburgh 29: 351. 1892. 
*STRASBURGER: Die Angiospermen und die Gymnospermen (1879). 7 be 
Jigs. 81-86. 
* MCKENNEY: Observations on the development of some embryo-sacs. Contrib. 
Bot. Lab. Univ. Pennsylvania 2: [no. 1] 80. 1898. 
